thumb.js

var createThumb = function(fileObj, readStream, writeStream) {

  var finalImageSize = 320;

  var orig = gm(readStream, fileObj.name())

  console.log("transforming");

  orig.size(function(err, size) {
    console.log(size,err); /// <<<--- this is the only place i can get the dimensions to cut crop
  });

  console.log(size);

  if (size.width > size.height) {
    cropSize = size.height;
    yCrop = 0;
    xCrop = (parseInt(size.width) - cropSize) / 2;
  } else {
    cropSize = size.width;
    xCrop = 0;
    yCrop = (parseInt(size.height) - cropSize) / 2;
  }

  var cropped = orig.crop(cropSize, cropSize, xCrop, yCrop);

  var resized = cropped.resize(finalImageSize, finalImageSize);

  resized.stream().pipe(writeStream);

};